Apple boss Tim Cook has branded his company's 13 billion euro (£11 billion) bill for unpaid taxes in Europe as "political crap", maddening and untrue.
The chief executive dismissed an audit by a Brussels watchdog which found it only paid 0.005% tax in 2014, and claimed the global tech brand paid a worldwide rate of 26.1% on its earnings that year.
"It's maddening. It's maddening and disappointing," the Apple chief said. "It's clear that this comes from a political place. It has no basis in fact or in law."
Mr Cook said the numbers had been set out in the company's quarterly accounts and that Apple paid 400 million US dollars corporation tax in Ireland in 2014, another 400 million US dollars of similarly classed tax in the US and set aside billions more for tax bills in America that year.
From his base in Cupertino, California, Mr Cook told Ireland's state broadcaster RTE that the European Commission was over-reaching and attempting to retroactively target Apple and Irish laws with a political ruling.
"When you are accused of something that is so foreign to your values, it brings out an outrage in you. That's how we feel," he said.
"Apple has always been about doing the right thing, never the easy thing."
Mr Cook spoke as Independent members of Ireland's fragile minority Government seek legal explanations of the 130-page ruling from Commissioner Margrethe Vestager and whether they should support Finance Minister Michael Noonan's call for an immediate legal challenge.
The watchdog's landmark ruling into the iPad and iPhone maker's tax affairs found it paid just 1% tax on its European profits in 2003 and 0.005% in 2014 after getting assurances from tax inspectors about its tax affairs and how it routed sales figures through subsidiaries in Ireland and on to the US.
The cabinet met on Wednesday but failed to reach agreement and will meet again on Friday as it puzzles over whether to accept the unprecedented windfall ordered by Brussels.
There have been calls for the Dail parliament in Dublin to be recalled to debate the issue with left-leaning groups insisting the billions should go towards public services.
Controversy has raged across the country on whether to pursue the unpaid tax and risk the wrath of multinationals, which the Irish economy depends heavily upon, or to fight the EU finding.
Despite the mammoth tax bill, Apple insists it will not abandon Ireland, where it has about 6,000 employees and is planning to build a huge data centre.
Mr Cook said that in 2014 his company paid one of every 15 US dollars of corporation tax in Ireland.
"I think the right thing here is to stand up and fight against this over-reach," he said.
"Clearly the sovereignty of the country is at stake and the rule of law and sovereignty of law are at stake."
He added: "I think both parties feel like the decision is wrong, is not based on law or facts. It's based on politics. I think we should stand up and say that very clearly."
In a separate interview with the Irish Independent, Mr Cook branded Ms Vestager's ruling "political crap".
"Our commitment to Ireland is unwavering. We are not going to let an invalid ruling, a politically based ruling, affect our deep commitment to Ireland."